// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "net/base/platform_mime_util.h"

#include <string>

#include "base/strings/utf_string_conversions.h"
#include "base/win/registry.h"

namespace net {

bool PlatformMimeUtil::GetPlatformMimeTypeFromExtension(
    const base::FilePath::StringType& ext, std::string* result) const
{
    // check windows registry for file extension's mime type (registry key
    // names are not case-sensitive).
    std::wstring value, key = L"." + ext;
    base::win::RegKey(HKEY_CLASSES_ROOT, key.c_str(), KEY_READ).ReadValue(L"Content Type", &value);
    if (!value.empty()) {
        *result = base::WideToUTF8(value);
        return true;
    }
    return false;
}

bool PlatformMimeUtil::GetPreferredExtensionForMimeType(
    const std::string& mime_type, base::FilePath::StringType* ext) const
{
    std::wstring key(
        L"MIME\\Database\\Content Type\\" + base::UTF8ToWide(mime_type));
    if (base::win::RegKey(HKEY_CLASSES_ROOT, key.c_str(), KEY_READ).ReadValue(L"Extension", ext) != ERROR_SUCCESS) {
        return false;
    }
    // Strip off the leading dot, this should always be the case.
    if (!ext->empty() && ext->at(0) == L'.')
        ext->erase(ext->begin());

    return true;
}

void PlatformMimeUtil::GetPlatformExtensionsForMimeType(
    const std::string& mime_type,
    std::unordered_set<base::FilePath::StringType>* extensions) const
{
    // Multiple extensions could have the given mime type specified as their types
    // in their 'HKCR\.<extension>\Content Type' keys. Iterating all the HKCR
    // entries, though, is wildly impractical. Cheat by returning just the
    // preferred extension.
    base::FilePath::StringType ext;
    if (GetPreferredExtensionForMimeType(mime_type, &ext))
        extensions->insert(ext);
}

} // namespace net
